CarBEN Model -- 1/24th scale model and 3D computer model for EV

[euromodder]

Originally Posted by Frank Lee

The increased weight of new cars is not due to unibody per se; it is partly due to gummint regs for all the onboard crap cars need to have now,

They earn their weight in hugely reduced pollution, even if they may cause a few gallons more fuel over the life of the car. At least there's a trade-off that's really worth it.

Keeping light old clunkers going may get good mpg and be good for your wallet, but unfortunately it's not quite so good for the environment.

and partly due to the boatload of options everything "needs" now.

Electric everything and almost trying to make a car interior into a sound studio is a real heavyweight mpg-killer.

If car manufacturers kept out most of the creature comfort options, they could build simple but cleaner cars for a lot less $$$, so less wealthy people who now keep old bangers going could get a chance to buy a far less polluting and safer car.

That's what Renault is doing with its revived Dacia brand.

[Frank Lee]

I'd wager safety equipment exponentially outweighs pollution control equipment. But the NVH reduction measures and other amenities add gobs of heavy sound-proofing and wiring.

[NeilBlanchard]

I'm going to build a 1/5th scale model, and I'll try to fiberglass it. I'm looking for 3-4mm thick birch "craft" plywood. The largest sheet size I can find is 12" x 24" -- I need 12" x 33".

Can you help me find this size or larger, please?

[gone-ot]

Originally Posted by NeilBlanchard

I'm going to build a 1/5th scale model, and I'll try to fiberglass it. I'm looking for 3-4mm thick birch "craft" plywood. The largest sheet size I can find is 12" x 24" -- I need 12" x 33".

Can you help me find this size or larger, please?

...check with custom guitar (luthier) builders, because they'll know about sources of thin, flexible, woods...in ALL sizes.

...acoustic guitar builders (rather than solid-body builders) would know best.

[NeilBlanchard]

That's a thought, though I think plywood is the best choice. A friend who builds a lot of radio controlled airplanes says he can buy 24" sq. 5-ply "craft" plywood at his local craft supply store. The one closest to me (same chain -- A C Moore) only has the 12" x 24". I can just squeak the biggest centerline section onto that size, with a few compromises.

I'm thinking I'm going to use wire and then fiberglass it.

[1.9SDI]

Have you looked into this technique? Excellent article:
Browser Warning

[NeilBlanchard]

That's one of the vehicles in the 'Zero Race' -- I have seen a bit about how they made it, but not as detailed as the page you linked to. Thanks, but I doubt I'll be able to try it.

[Rokeby]

Neil,

Perhaps I can help with some of the matters you've raised lately.

Unless you're dealing with a small hobby shop or similar concern, virtually
every one buys "Sheet goods," ie, plywood in 4'x8' or 5'x10' sheets. They
then cut it up into smaller pieces for resale on a panel saw. At Home Despot,
Lowes, etc, ask for the wood products area manager(?) and ask about buying
an uncut sheet.

For the very highest quality plywood required by the FAA in "experimental,"
ie, home-built aircraft try these folks, be sure to check out their composites
section too:
Plywood from Aircraft Spruce

For spanning large flat areas, you might want to consider "composite panels."
Typically they are aluminum skins over honey comb or high density foam.
Very rigid, very light. Can also be done with ply skins. Best to do your own
Googling on this.

Originally Posted by NeilBlanchard

Here's the 1:12 model in process:

Whether it's a 1:5 scale or full size, part accuracy is going to make or break
the effort. I'm thinking a relatively inexpensive 2-axis CNC machine is what
you'll be needing. Here's one made specifically for sheet goods, comes as a
kit for ~$1000 USD. Perhaps most importantly, it will cut directly from
Sketch Up files:


I think the kit parts are made on one of these mahines.

Phlatprinter 3 Kit

[NeilBlanchard]

I will probably order some plywood from that source -- thank you.

I saw this cutter on the other thread -- it looks awesome. If it can cut aluminum or plywood, it would be a great tool to have, that's for sure!

On a related note, my son tells me that he saw an add on for Half Life 2 (related the "Garry's Mod"?) that can do CFD with a converted SketchUp file. You put a motor in it, and give it a weight, and you "drive" it! He is still following up on the details; so if it does actual CFD analysis, or if you simply put virtual "tufts" on the car as you drive it, I don't know. But, the thought of getting any semi-realistic aerodynamic test on the CarBEN EV model as being possible, is a good thing.

[Rokeby]

Thinking more about the usability of the PhlatPrinter;

You could use it to quickly make a solid model of the car.
Just get thin slices from Sketch Up. Depending on the size,
say for a 12:1 scale 1 ft(real) = 1 inch (model), 1/4 in thick
slices stacked front to rear.

The temptation would be great to use plywood. Don't, the
alternating end grain will cause serious problems painting/
finishing later. Go for a not too soft, solid wood with a
suppressed grain like clear white pine or tulip poplar.

Once the "lifts" are carefully glued up, carve off the corners,
sand smooth and finish.

Voila! A 3D model you could take to any investor's/IPO meeting.